An ultrasonic diagnostic device is a device which constructs a diagnostic image by a reflection echo obtained from an ultrasound probe. The ultrasound probe has a transducer which is arranged to perform electroacoustic conversion, converts an electrical signal supplied from the ultrasonic diagnostic device to an ultrasonic wave and transmits the ultrasonic wave to an object, and converts a reflection echo signal generated from the object to a reception signal.
In recent years, an ultrasound probe using a transducer, called a CMUT (Capacitive Micromachined Ultrasound Transducer), has been put into practical use. The CMUT is a capacitive micromachined ultrasound probe which is formed by a semiconductor micromachining process. A CMUT chip which is mounted on an ultrasound probe has a structure in which multiple elements (CMUT cells) each having a drum-like shape of a musical instrument are aggregated, and a portion of each CMUT cell corresponding to the membrane (vibrating membrane) vibrates, thereby performing sound pressure-voltage conversion.
The CMUT has a characteristic in which transmission and reception sensitivity of an ultrasonic wave changes depending on a bias voltage to be applied. However, as is also known, even if the same bias voltage is applied, variation in transmission and reception sensitivity is generated among a plurality of CMUT cells, due to manufacturing variation or residual stress.
In the ultrasonic diagnostic device of the related art, in order to correct variation in transmission and reception sensitivity, an ultrasonic output signal or electrostatic capacitance of each of the CMUT cells is measured, and a corrected bias voltage is applied to each of the CMUT cells (for example, see Patent Literature 1).